Process fob improving drying



Patented July. 25, 1939 PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Theodore s. Hodgins, mm Oak, Mica, minor to- Belclihold Chemicals, Inc., formerly Beck, Koller & Company, Inc, Detroit, Mich.

No Drawing.

Application November 16, 1938,

Serial No. 240,858

4 Claim (Cl. 260-408) In common with the disclosure of my Patent No. 2,133,894, dated October 18, 1938, the present invention relates broadly to a process for improving the drying properties of raw oils containing naturally occurring anti-oxidants.

According to the process set forth in said pat.-

ent it was shown that the drying properties of such oils could be improved by treating the oils preferably at substantially room temperature 10 'with a relatively strong inorganic oxidizing agent provided the pH value of the solution was maintained close to the neutral point while avoiding exact neutrality, by the use of either an alkaline or an acid reagent in certain specified quantities is with respect to the weight of the oil. The optimum range in the case of the alkali was found to be .013-.050 parts by weight of alkali to 100 parts by weight of the oil, and in'the case of the acid reagent the range was .025-.050 parts by, weight 20 of acid to 100 parts by weight of the oil being treated.

The present invention is specifically directed to the improving of oils using an organic oxidizing agent such for example as benzoyl peroxide.

V 25 The process is generally similar to that employed when using inorganic oxidizing agents exceptthat the proportions of acid or alkali desirably employed in the process is found to be very much greater where an organic oxidizing agent is em- 30 ployed than where an inorganic oxidizing agent is used. Thus in the case of an inorganic oxidizing agent the quantity of acid or alkali employed should be considerably less than 1% by weight of the oil being treated, while in the case 85 of an organic oxidizing agent the acid or alkaline reagent employed may be from 1 to 5% by weight of the oil, the optimum being near the lower limit as for example from 1 to 1.5%. v

The preferred quantity of organic oxidizing agent employed may be expressed as falling substantially within the range of .5 to 1.5% by weight of the oil or approximately 1% by weight of oil. Various types of oils containing naturally occurring anti-oxidants may be improved as to their drying properties by treatment in accordance with the present process, among which may be mentioned by way of example linseed oil, sun flower oil, perilla oil, rape seed oil and oiticica oil.

The length of time required for treating these oils is determined by the first measurable increase in refractive index or by a corresponding decrease in iodine number. The method of treatment of an 011 comprises treating the oil preferably at ll room temperature with organic oxidizing agents such as peroxides in an alcoholic or aqueous solution within the limited alkaline or acid range referred to above. The process effectively removes the anti-oxidants (such as lecithin and kephalin) which are naturally occurring in these 5 oils. The sludge containing the anti-oxidants and spent reagents may be separated from the refined oil in any suitable manner, such as filtering or centrifuging, depending on the nature of the treating solution. In the case of alcoholic solutions the excess alcohol may be removed by distillation.

I am aware that previous attempts have been made to improve the drying properties of oils by partially oxidizing the same, particularly by passing air or other oxidizing gas through the body of the oil. My invention is not concerned with this type of oxidation. In such prior processes the oxidation has taken place within the oil itself whereas according to my process only the anti-oxidants are eliminated, the oil being unoxidized. Also in such previous treatments temperatures above room temperature have been considered necessary whereas my process may be carried on to best advantage at substantially room temperature.

It has also been proposed to treat various oils with chemical reagents such as acids, alkalies and salts for the purpose of improving their qualities, as for example for removing odors, or

for bleaching the same, but to my knowledge no successful process has been carried out wherein the antioxidants are removed by treatment at room temperature with an oxidizing agent and with controlled acidity or controlled alkalinity with respect to the oil.

According to my process I regulate the acidity or alkalinity of the treating solution, maintaining a predetermined value on the acid or slightly on the alkaline side. I find that at the neutral point (pH of 7.0) it is impossible to effectively treat the oil for the purpose herein set forth, and also if the acidity or alkalinity exceeds a certain predetermined limit, the process becomes less and less effective until a point is reached where substantially no improvement occurs. Accordingly my process consists in treating the oils with a relatively strong organic oxidizing agent in low concentration with respect to the oil, and within predetermined limits on the acid or alkaline side.

The invention will be further understood by reference to the following specific examples which are intended as illustrative only and not as in any way limiting the invention:

Example 1 v Parts by weight Soya bean oil 100. Hydrochloric acid 1.0 Benzoyl peroxide 1.5 Water (not constant) 1.0-10

The oil is preferably treated for approximately one-half hour and is mechanically agitated either by means of a stirrer or by blowing filtered air or an inert gas through the material, it being understood that the air or gas employed functions solely as an agitating means and does not in any way enter into the reaction. The time may be varied according to the particular conditions employed, the exact time in any particular instance being determined by a refractive index curve such as shown in Fig. 2 of my prior Patent No. 2,133,894. The complete destruction of anti-oxidants is determined when the refractive index firsbbegins to increase. The treatment may be carried out at substantially room temperature and the decomposed impurities filtered or otherwise separated out. The resultant oil is found to be much improved in drying properties as compared to the original oil and has a slightly lighter color. A film of this treated oil when baked for one hour at 200 F. proves to be harder than the best refined linseed oil subjected to the same bake.

Example 2 Parts by weight soya bean oil 100 KOH 1 Benzoyl peroxide 1.5 Alcohol 1.0-10

The mixture is agitated mechanically as set forth in the preceding example and the oil is separated from the treating media by filtration and distillation of the alcohol. Good results are obtained by treating the oil for approximately one-half hour at room temperature. This time can be varied considerably without departing from the spirit of the invention. The resulting oil possesses the properties referred to in the preceding example.

While soya bean oil has'been referred to in the above examples it will be understood that various other oils may be substituted with similarly improved drying properties in the final product. Furthermore other organic oxidizing agents than benzoyl peroxide may be employed within the scope of the invention.

I claim:

1. A process for improving the drying quality of raw oils containing naturally occurring antioxidants, which comprises removing the .antioxidants by treating the oils at substantially room temperature with an organic oxidizing agent comprising benzoyl peroxide in the proportion of about 1% by weight of the oxidizing agent as compared with the weight of the oil being treated, maintaining the pH value of the treating solution on the acid or alkaline side throughout the treatment by the addition of 1-5% by weight of an acid or alkaline reagent, continuing the treatment until the refractive index begins to increase, and separating the treated oil from the other; constituents.

2. A process as set forth in claim 1, wherein the pH value is maintained on the acid side by the addition of hydrochloric acid in aqueous solution. v

3. A process as set forth in claim 1, wherein the pH value is maintained on the alkaline side by the addition of KOH in alcoholic solution.

4. A process as set forth in claim 1, wherein the oil treated is soya bean oil.

THEODORE S. HODGINS. 

